Well, what do you mean by having too many interactions? As in it can be used with many things or it would have a variety of effects?
Can I have your opinion on both?
Well, I don't see an issue with it affecting many things. In fact, that would be as expansive as any control or buff spell in the game right now, since they target a majority of the card pool with varying effects. As long as the effect is consistent, it should be fine.
I assume what you had meant was the latter, similar to, for the sake of comparison, the RtR Charms, where there are multiple effects to one card where it isn't all of them, but only one. In Elements, I don't think that would be for the best since with the current card pool, you essentially have multiple cards for one, which allows for other cards to take its place, which makes it overshadow cards with similar effects.
Of course, this can be remedied by a higher cost, but then that makes it a pointless idea since, for the sake of speed or consistency, it would be replaced by their cheaper counterparts.
My thoughts are that it's fine if it has two effects AT MOST, implemented as an IF/ELSE card [If card is Fire, +2/+0, else -3/-3]. Any more, and the design gets quickly cluttered and messy.